Physical quantity sensor having movable portion

Abstract

An angular rate sensor includes: a support substrate; a semiconductor layer; and a movable portion. The movable portion includes a driving vibration portion and a detecting vibration portion. The driving vibration portion is capable of vibrating in a first direction. The detecting vibration portion is capable of vibrating in a second direction. The driving vibration portion includes through holes, and the detecting vibration portion includes thorough holes. Each through hole of the driving vibration portion has an elongated shape extending in the first direction. Each through hole of the detecting vibration portion has an elongated shape extending in the second direction.

1. An angular rate sensor comprising:
 a support substrate; 
 a semiconductor layer supported on the support substrate; and 
 a movable portion disposed in the semiconductor layer, wherein 
 the movable portion is movably supported on the support substrate, 
 the movable portion includes a driving vibration portion and a detecting vibration portion, 
 the driving vibration portion is capable of vibrating in a first direction, 
 the detecting vibration portion is capable of vibrating in a second direction by angular velocity applied to the sensor, 
 the second direction is perpendicular to the first direction, 
 the driving vibration portion includes a plurality of through holes, which penetrate in a thickness direction of the semiconductor layer, 
 the detecting vibration portion includes a plurality of through holes, which penetrate in the thickness direction of the semiconductor layer, 
 each through hole of the driving vibration portion has an elongated shape extending in the first direction, and 
 each through hole of the detecting vibration portion has an elongated shape extending in the second direction. 
 
   
   
     2. The sensor according to  claim 1 , wherein
 the detecting vibration portion is connected to the support substrate through a detection beam, which is movable in the second direction, and 
 the driving vibration portion is connected to the detecting vibration portion through a driving beam, which is movable in the first direction. 
 
   
   
     3. The sensor according to  claim 1 , wherein
 the through holes of the driving vibration portion provide a brick pattern, and 
 the through holes of the detecting vibration portion provide a brick pattern. 
 
   
   
     4. The sensor according to  claim 3 , wherein
 the through holes of the driving vibration portion provide a plurality of lines, each of which is alternately aligned, and 
 the through holes of the detecting vibration portion provide a plurality of lines, each of which is alternately aligned. 
 
   
   
     5. The sensor according to  claim 1 , wherein
 each through hole of the driving vibration portion has a rectangular shape, a wide side of which is parallel to the first direction, and 
 each through hole of the detecting vibration portion has a rectangular shape, a wide side of which is parallel to the second direction. 
 
   
   
     6. A physical quantity sensor comprising:
 a support substrate; 
 a movable portion supported on the support substrate in such a manner that the movable portion is movable in a horizontal direction of the substrate when physical quantity is applied to the sensor; 
 a periphery frame portion disposed around the movable portion and fixed on the support substrate; 
 a semiconductor layer supported on the support substrate, wherein, 
 the movable portion and the periphery frame portion are provided by the semiconductor layer, 
 the movable portion includes a driving vibration portion and a detecting vibration portion, 
 the driving vibration portion is capable of vibrating in a first direction, 
 the detecting vibration portion is capable of vibrating in a second direction by the physical quantity applied to the sensor, 
 the second direction is perpendicular to the first direction, 
 the driving vibration portion includes a plurality of through holes, which penetrate in a thickness direction of the semiconductor layer, 
 the detecting vibration portion includes a plurality of through holes, which penetrate in the thickness direction of the semiconductor layer, 
 each through hole of the driving vibration portion has an elongated shape extending in the first direction, and 
 each through hole of the detecting vibration portion has an elongated shape extending in the second direction, 
 the physical quantity is detected on the basis of a displacement of the movable portion when the physical quantity is applied to the sensor, and 
 the periphery frame portion has an electric potential higher than an electrical potential of the support substrate and an electrical potential of the movable portion. 
 
   
   
     7. The sensor according to  claim 6 , wherein
 the periphery frame portion is fixed and supported on the support substrate through an insulation layer. 
 
   
   
     8. The sensor according to  claim 6 , wherein
 the movable portion is separated from the support substrate, 
 the periphery frame portion includes a pad for applying electric potential to the periphery frame portion, 
 the movable portion and the periphery frame portion are provided by a semiconductor layer, and 
 the pad is disposed on the semiconductor layer. 
 
   
   
     9. The sensor according to  claim 6 , wherein
 the detecting vibration portion is connected to the support substrate through a detection beam, which is movable in the second direction, and 
 the driving vibration portion is connected to the detecting vibration portion through a driving beam, which is movable in the first direction. 
 
   
   
     10. The sensor according to  claim 6 , wherein
 the through holes of the driving vibration portion provide a brick pattern, and 
 the through holes of the detecting vibration portion provide a brick pattern. 
 
   
   
     11. The sensor according to  claim 10 , wherein
 the through holes of the driving vibration portion provide a plurality of lines, each of which is alternately aligned, and 
 the through holes of the detecting vibration portion provide a plurality of lines, each of which is alternately aligned. 
 
   
   
     12. The sensor according to  claim 6 , wherein
 each through hole of the driving vibration portion has a rectangular shape, a wide side of which is parallel to the first direction, and 
 each through hole of the detecting vibration portion has a rectangular shape, a wide side of which is parallel to the second direction.